Many integrated circuits (ICs) are made up of millions of interconnected devices, such as transistors, resistors, capacitors, and diodes, on a single chip of semiconductor substrate. It is generally desirable that ICs operate as fast as possible, and consume as little power as possible. Semiconductor ICs often include one or more types of memory, such as complementary metal-oxide-semiconductor (CMOS) memory, antifuse memory, and Efuse memory.
One-time-programmable (“OTP”) memory elements are used in ICs to provide non-volatile memory (“NVM”). Data in NVM are not lost when the IC is turned off. NVM allows an IC manufacturer to store lot numbers and security data on the IC, for example, and is useful in many other applications. One type of NVM utilizes electrical fuse (eFuse) technology.
EFuses are typically integrated into semiconductor ICs by using a narrow strip (commonly referred to as a “fuse link”) of conducting material (metal, poly-silicon, etc.) between two pads, generally referred to as anode and cathode. Applying a program current to the eFuse destroys (i.e., fuses) the link, thus changing the resistivity of the eFuse. This is commonly referred to as “programming” the eFuse.